1. Field of the Invention:
The present invention relates to well devices employed in the completion and production of oil and gas wells. More specifically, the invention relates to a well tubing hanger which is retrievably anchored in a subsurface location within a well casing or other well conduit and which is releasable by a straight pull on the tubing string extending from the well surface.
2. Description of the Prior Art:
Anchor-seal assemblies of various types have been used in the past in well working operations, and in the production of a well. For instance, seal assemblies in the form of packers are known for isolating formations for treatment, or for isolating segments of liners or well casings. Packers are routinely used for sealing production strings to well liners or well casings to define flow paths from producing formations to the well surface.
Particularly in the case of packers, the seal assembly is usually positioned within a well by means of a pipe string, and then set in sealing and anchoring engagement with the surrounding conduit. The setting operation usually involves the movement of multiple components of the packer to expand one or more resilient seal members, and to wedge anchoring slips against the surrounding well conduit or casing.
In order to release the packer, it was often necessary to manipulate the pipe string leading to the well surface in various ways such as rotating or setting down weight on the pipe string. In other cases, it was necessary to run a separate release tool down the pipe string to the packer in order to release the packer.
In spite of advances in the art, a need exists for a pack-off well apparatus which is adapted for specific, demanding environments.
A need also exists for such a pack-off apparatus which can be released from the set position and retrieved to the well surface by a straight pull on the pipe string extending from the well surface to the packer.
A need also exists for a pack-off well apparatus, such as a tubing hanger, which eliminates flow ports in the production tubing or work string, or a component in direct fluid communication therewith, of the type used to provide actuating fluid from the bore of the production tubing to well tools to initiate desired operations, such as the setting of the packing element. Seals employed with such ports must be sealed in subsequent operations and are subject to deterioration and hence leakage.
The above noted needs are met by the apparatus described in the specification which follows.